A conventional fixed-wing unmanned aircraft (UA) includes a left fuel bladder disposed in a left wing of the fixed-wing UA and a right fuel bladder disposed in a right wing of the fixed-wing UA. The left and right fuel bladders connect to a T-shaped coupling which leads to a fuel delivery subsystem that draws fuel for the engine of the fixed-wing UA.
During flight, the fuel delivery subsystem supplies fuel which is consumed by the engine to propel the fixed-wing UA forward. As the fuel bladders empty, the fixed-wing UA becomes lighter.